Performance on Drilling Machine

2.1   Introduction

Drilling is an operation through which holes are produced in a solid metal by means of a revolving tool called a drill. Since it is not possible to produce a perfectly true note by drilling, it is considered a roughing operation. Obviously, therefore, where a very close dimensional accuracy is to be maintained, this forms only the basic operation. For such holes, drilling is followed by another operation called reaming, in which the required dimensional accuracy and fine surface finish are obtained by means of a multi-tooth revolving tool called a reamer.

2.2  Components of drilling machine

Fig. 2.1 shows a general configuration of the drilling machine, column drill in particular. The salient parts are

Fig. 2.1  Drilling machine

• Column with base : It is the basic structure to hold the other parts
• Drilling head : This box type structure accommodates the power drive and the speed and feed gearboxes.
• Spindle : Holds the drill and transmits rotation and axial translation to the tool for providing cutting motion and feed motion both to the drill. Drilling machines are available in varying size and configuration such as pillar drill, column drill, radial drill, micro-drill etc. but in working principle all are more or less the same.

2.3  Operations performed on drilling machine

Various operations performed by a drilling machine are enlisted below:

1. 1. Drilling 
   2. Boring
   3. Counter boring
   4. Counter sinking  
   5. Reaming
   6. Tapping   
   7. Trepanning.
   8. Spot facing      
   9. Lapping               

2.4  Specification of a Drilling Machine

A heavy duty drilling machine is specified by following parameters.

1. Drilling capacity
2. Taper in spindle (Morse no.)
3. Distance between spindle and column (maximum and minimum), in case of radial drilling machine
4. Transverse of spindle
5. Minimum distance between spindle and table
6. Minimum distance between spindle and base plate
7. Working surface of table (i.e., diameter)
8. Range of spindle speeds
9. Range of power feed per revolution
10. Motor speed, and
11. Motor power

Table 2.1 – Specification of 20 mm light duty pillar drilling machine

Actual Job Photographs :